System and method for strengthening a sloped structure such as a berm, basin, levee, embankment, or the like

ABSTRACT

Embodiments of the invention comprise a system for strengthening a sloped structure such as a berm, basin, levee, or embankment. The comprises first and second opposing sides, the second side being adjacent the sloped structure; a bottom side adjoining bottom edges of the first and second sides, thereby forming a cavity within the first, second, and bottom sides; fill material disposed within the cavity; an impermeable membrane encapsulating at least a portion of the fill material; and a plurality of reinforcing members disposed within the fill material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of and claims priority toco-pending U.S. application Ser. No. 13/018,515, filed Feb. 1, 2011,which in turn is a continuation-in-part of and claims priority toco-pending U.S. application Ser. No. 12/757,096, filed Apr. 9, 2010,which in turn is a continuation-in-part of and claims priority toco-pending U.S. application Ser. No. 12/636,201, filed Dec. 11, 2009,which in turn claims priority to provisional U.S. Application No.61/267,593, filed Dec. 8, 2009, the contents of which are incorporatedherein by reference in their entirety.

FIELD OF THE INVENTION

The present invention generally relates to construction of containmentberms and other embankments and structures.

BACKGROUND OF THE INVENTION

Berms are commonly used in situations where the ability to constructvertically has been constrained by the inability to expand laterally ata slope that allows the desired vertical height to be attained withoutfailure. For example, berms are often used to expand the capacity oflandfills that are nearing or have reached their capacity but which donot have space to expand outward. In such situations, berms may beconstructed around some or all of the landfill to increase the verticalcapacity. Referring now to FIG. 1, a landfill 10 comprises a largewaste-receiving recess 12 in the ground 14. The recess has a surface 16that may or may not have a liner system in place. The waste in thelandfill may comprise any material that is typically placed in alandfill, such as municipal solid waste (MSW), residential waste,industrial waste, fossil fuel combustion material, construction debris,hazardous waste and/or yard waste, etc. The recess is surrounded by anedge 18. The edge is typically substantially horizontal, but mayalternatively be substantially sloped. As seen in FIG. 1, the existingaccumulation of waste 20 has filled the recess 12. However, the capacityof the landfill can be increased by constructing a berm on the edge 18.

Berms often comprise a reinforced portion and backfill material. Thereinforced portion comprises structural fill material with reinforcingmembers disposed (typically substantially horizontally) therein. Theseberms allow for the desired vertical height in a limited space. Theseberms are very expensive to construct, however, on a relative basis, asmaterial with very tight specifications must be acquired and transportedand the cost of the reinforcement itself can be prohibitive in manycircumstances. Therefore what is needed is a method to construct theseberms that allows for economical construction and that utilizes materialthat can generate the revenue necessary to cover the bulk of the cost ofthe entire berm while being environmentally sound and regulatory agencyacceptable.

BRIEF SUMMARY OF THE INVENTION

In one embodiments of the invention, a system for strengthening a slopedstructure comprises first and second opposing sides, the second sidebeing adjacent the sloped structure; a bottom side adjoining bottomedges of the first and second sides, thereby forming a cavity within thefirst, second, and bottom sides; fill material disposed within thecavity; an impermeable membrane encapsulating at least a portion of thefill material; and a plurality of reinforcing members disposed withinthe fill material.

In addition to the system for strengthening a sloped structure, asdescribed above, other aspects of the present invention are directed tocorresponding methods for strengthening a sloped structure.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

Having thus described the invention in general terms, reference will nowbe made to the accompanying drawings, which are not necessarily drawn toscale, and wherein:

FIG. 1 is a simplified cross-sectional diagram of a prior art landfillthat would benefit from embodiments of the present invention;

FIG. 2 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with one embodimentof the present invention;

FIG. 3 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 4 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 5 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 6 is a simplified cross-sectional diagram of a berm for creating anew landfill or laterally increasing the capacity of an existinglandfill, in accordance with an alternative embodiment of the presentinvention;

FIG. 7 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 8 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 9 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 10 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 11 is a simplified cross-sectional diagram of a berm for creating alandfill or laterally increasing the capacity of an existing landfill,in accordance with an alternative embodiment of the present invention;

FIG. 12 is a simplified cross-sectional diagram of a berm for creating alandfill, in accordance with an alternative embodiment of the presentinvention;

FIG. 13 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 14 is a simplified cross-sectional diagram of a berm for creating alandfill or laterally increasing the capacity of an existing landfill,in accordance with an alternative embodiment of the present invention;

FIG. 15 is a simplified cross-sectional diagram of a berm, in accordancewith an alternative embodiment of the present invention;

FIG. 16 is a partial top cutaway view of a drainage system of a berm forincreasing the capacity of an existing landfill, in accordance withembodiments of the present invention;

FIG. 17 illustrates simplified cross-sectional diagrams of a Subtitle Dlandfill liner and two possible equivalents thereof;

FIG. 18 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 19 is a simplified cross-sectional diagram of a berm for creating alandfill or laterally increasing the capacity of an existing landfill,in accordance with an alternative embodiment of the present invention;

FIG. 20 is a simplified cross-sectional diagram of a berm, in accordancewith an alternative embodiment of the present invention;

FIG. 21 is a simplified cross-sectional diagram of a berm for increasingthe capacity of an existing landfill, in accordance with an alternativeembodiment of the present invention;

FIG. 22 is a simplified cross-sectional diagram of a berm for creating alandfill or laterally increasing the capacity of an existing landfill,in accordance with an alternative embodiment of the present invention;

FIG. 23 is a simplified cross-sectional diagram of a portion of the bermof FIG. 21;

FIGS. 24A-C are simplified cross-sectional diagrams of a system forstrengthening a slope of a containment structure, in accordance withembodiments of the present invention;

FIG. 25 is a simplified cross-sectional diagram of a system forstrengthening a slope of a containment structure, in accordance with analternative embodiment of the present invention;

FIG. 26 is a simplified cross-sectional diagram of a system forstrengthening a slope of a containment structure, in accordance with analternative embodiment of the present invention;

FIG. 27 is a simplified cross-sectional diagram of a system forstrengthening a slope of a containment structure, in accordance with analternative embodiment of the present invention;

FIG. 28 is a simplified cross-sectional diagram of a system forstrengthening a slope of a containment structure, in accordance with analternative embodiment of the present invention; and

FIG. 29 is a simplified cross-sectional diagram of a system forstrengthening a slope of a containment structure, in accordance with analternative embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now will be described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art. Likenumbers refer to like elements throughout.

The combustion of coal or wood in coal or wood fired power plantsproduces several materials, including: fly ash, bottom ash, boiler slag,and flue gas desulphurization (FGD) material. Together, these materialsrepresent what is generally referred to as ash or sometimes asFFCPs—Fossil Fuel Combustion Products. These materials arewell-documented sources of heavy metal contamination in air, water andon land. Contaminants include selenium, mercury, lead, boron, cadmium,thallium, polycyclic aromatic hydrocarbons compounds, etc. There is anincreased awareness and concern regarding the long term health effectsof these materials on both humans and the environment as thesecontaminants can become mobile if not sequestered properly.

FFCPs generally are a very good material suitable for utilization inembankments, re-enforced embankments, walls, berms, roadways, etc. asthey tend to be coarse in nature and offer superior shear strength,possess a high friction angle, and have high bearing capacity.Currently, approximately 53 million tons/year of the 130 milliontons/year of FFCPs produced are beneficially used in structural,concrete, wall board and other applications. Upcoming regulatory changesmay require that FFCPs be treated as contaminated waste, therebyeliminating many of the uses and producing a pronounced strain on theeconomy. Additionally, landfill capacity across the United Sates will beseverely stressed to handle the increased demand for simply disposing ofthese FFCPs. The utilization of FFCPs and other contaminated materialsin embodiments of the present invention will offer a suitable,environmentally-, regulatory- and financially-sound alternative use ofthese types of materials.

In addition, during the development and use of land for manyresidential, commercial, agricultural, industrial and other purposes,non-hazardous contaminated soils and media (concrete, asphalt, glass,etc.) are created. These materials can be contaminated with metals,acids, bases, volatile and semi-volatile organic compounds, petroleumproducts, and a host of other contaminates. These materials are welldocumented sources of contamination in air, water and on land. There isan ongoing and increased awareness and concern of the long term healtheffects of these materials on both humans and the environment as theseelements can become mobile if not sequestered properly as well. Thesematerials, although tainted, are nonetheless valuable for certainbeneficial uses, including as a fill (structural or backfill) materialin reinforced embankment applications.

The materials (FFCPs and contaminated soils/media) used in embodimentsof the invention encompass a very broad entire spectrum of soil andmaterial types and could be characterized as fine grained, coarsegrained, homogeneous, non-homogeneous, etc. However characterized, inthe embodiments described herein, the material available can be used toconstruct berms for landfill expansion, roadway and berm constructionand are readily available in most locations.

A berm according to embodiments of the present invention may be used toexpand the capacity of a landfill. Such a berm is typically constructedon at least a portion of the upper, outer edge (18 of FIG. 1) of alandfill. Such a berm raises the height of the exterior walls of alandfill, thereby enlarging the waste-receiving recess (12 of FIG. 1).Such a berm may be of any suitable height, commonly about thirty toeighty feet tall. Such a berm may be of any suitable length, commonlyhundreds or even thousands of feet long. At least a portion of such aberm would sit on at least a portion of the edge surface of thelandfill, and the berm is substantially parallel to correspondingportions of the outer perimeter. Alternatively, a berm according toembodiments of the present invention may be used to create a newlandfill by constructing one or more such berms around the desiredperimeter of the new landfill. In such an alternative embodiment, theone or more berms define and create the waste-receiving recess of thelandfill.

Referring now to FIG. 2, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with one embodiment of the present invention. The berm 102 ofFIG. 2 comprises a reinforced portion 104 and backfill material 112. Thereinforced portion 104 is constructed using typical constructiontechniques and comprises structural fill material 106 and a plurality ofreinforcing members 108 disposed (typically horizontally) therein. Thereinforced portion may have a foundation of granular fill material 110.As seen in FIG. 2, the reinforced portion has opposing inner and outersurfaces. The outer surface is commonly termed the “face” of the walland the inner surface is adjacent the backfill material. The reinforcedportion may optionally have facing material covering the face of thereinforced portion. The facing material, if present, is typicallyattached to or integral with the reinforcing members. The structuralfill typically comprises relatively homogeneous soils that arerelatively free of debris, foreign objects, excess silt, roots, andorganics. The granular fill is typically well graded sand, well gradedsand and gravel, crushed stone, or other approved granular material.

The backfill material 112 comprises contaminated fill material. Thecontaminated fill material can be any suitable waste product that hasthe desired coarseness, shear strength, high friction angle, and highbearing capacity. The contaminated fill material should benon-hazardous, but is nonetheless expensive to properly dispose of. Thecontaminated fill material may comprise FFCPs, non-hazardouscontaminated soils, contaminated crushed glass, contaminated crushedconcrete, contaminated crushed asphalt, sand blast grit, foundry sands,properly de-watered dredge spoils, and combinations of these materials.Importantly, the backfill material is at least partially encapsulated byan impermeable membrane 114. FIG. 2 illustrates a berm with a partiallyencapsulated backfill. In the embodiment of FIG. 2, the portion 116 ofthe backfill material adjacent the existing waste accumulation is notcovered by an impermeable membrane.

The impermeable membrane is, when intact, impermeable to fluids and/orgases. The impermeable membrane used in embodiments of the invention maycomprise, for example, a geomembrane, a compacted low permeability clayliner, a geosynthetic clay liner (GCL), geomembrane laminatedGeosynthetic Clay Liner, etc., or liner systems that will typicallyconform to Subtitle D of the Resource Conservation and Recovery Act(RCRA), conform to an approved equivalent of Subtitle D of RCRA(described in further detail below), or conform to a liner and/or coversystem requirement of any appropriate regulatory agency. The geomembranemay comprise one of low-density polyethylene (LDPE), high-densitypolyethylene (HDPE), polyvinyl chloride (PVC), polyurea or polypropylene(PP). Because of the potentially large size of such a berm and thelimited size of commercially available geomembranes, the impermeablemembrane may comprise a plurality of impermeable membrane sectionsjoined with impermeable seams. The plurality of impermeable membranesections are typically joined using any desirable method of joining suchmaterial, including but not limited to extrusion welding, solventwelding, fusion welding, and/or gluing (especially for PVC or PP).

In the embodiments illustrated in FIGS. 2-4, the backfill material hasan inner surface adjacent the inner surface of the reinforced portion,opposing top and bottom surfaces, and upper and lower sloped outersurfaces. The lower sloped outer surface slopes outward and upward fromthe bottom surface to the upper sloped outer surface. The upper slopedouter surface slopes outward and downward from the top surface to thelower sloped outer surface. The lower sloped outer surface is adjacentthe existing accumulation of waste 20 (the lower sloped outer surfacesits on at least a portion of the existing accumulation of waste), andthe upper sloped outer surface is adjacent a future accumulation ofwaste 130 (at least a portion of the future accumulation of waste sitson the upper sloped outer surface). In the embodiments of FIGS. 2-3, afirst liner portion 120 is disposed between the bottom surface and atleast a portion of the edge surface and a second liner portion 122 isoptionally disposed between the upper sloped outer surface and thefuture accumulation of waste 130. The liner portion disposed between theexisting accumulation of waste 20 and the future accumulation of waste130 is optional. The first and second liner portions will typicallyconform to Subtitle D of the Resource Conservation and Recovery Act(RCRA), conform to an approved equivalent of Subtitle D of RCRA(described in further detail below), or conform to a liner and/or coversystem requirement of any appropriate regulatory agency. Embodiments ofthe invention may utilize any suitable liner and/or cover system. Forsimplicity, the liner portions of embodiments of the invention will bereferred to herein as “Subtitle D or equivalent” liners or linerportions, however this is not intended to be limiting and embodiments ofthe invention are not limited to liners that conform to Subtitle D ofRCRA or equivalents thereof. If the first and/or second liner portionscomprise a Subtitle D or equivalent liner that has a geomembrane layer,the geomembrane that encapsulates the backfill material may functionadditionally as the geomembrane layer of the Subtitle D or equivalentliner. In other words, the geomembrane that encapsulates the backfillmay perform double duty in that the geomembrane functions both as theencapsulating material and as a layer of the Subtitle D or equivalentliner.

In some embodiments of the invention, the Subtitle D or equivalent linermay be omitted and a geomembrane by itself used in place of the SubtitleD or equivalent liner if permitted by the appropriate governmentalauthorities. Advantageously, if a geomembrane is permitted to be used inplace of the Subtitle D or equivalent liner, the geomembrane 114 thatpartially or fully encapsulates the backfill material will function asthe replacement for the Subtitle D or equivalent liner and no additionalliner is necessary (as above, the encapsulating geomembrane isperforming two functions). The landfill of FIGS. 2 and 3 has a SubtitleD or equivalent liner 118 covering the surface of the waste-receivingrecess, although embodiments of the invention may be used with alandfill that has no liner system in place.

Referring now to FIG. 3, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 142 of FIG. 3 comprises a reinforced portion 104 and backfillmaterial 152. The reinforced portion 104 of FIG. 3 is identical to thatof FIG. 2. The backfill material 152 is similar to that of FIG. 2 inthat it comprises contaminated fill material, such as FFCPs orcontaminated but non-hazardous soil. However, the backfill material ofFIG. 3 is fully encapsulated by an impermeable membrane 144. Unlike theberm of FIG. 2, the portion 116 of the backfill material adjacent theexisting waste accumulation is covered by an impermeable membrane 144 inFIG. 3.

Depending on the nature of the backfill material, it may be desirable tokeep water from reaching the backfill material. This is why animpermeable membrane is used. However, liquid may be released from thebackfill after placement. Therefore, it may be desirable to have anoptional drainage system (commonly termed a “toe drain”) within theencapsulation to drain away any water that is released from thebackfill. The drainage system of FIG. 3 comprises a perforated pipe 154running along at least a portion of the length of the berm. The pipe 154is surrounded by a granular fill material 156. An optional plurality ofdrainage pipes (not illustrated) may each lead substantiallyperpendicularly from the perforated pipe to an area outside of the berm.The drainage pipes may either lead toward the face of the reinforcedportion and exit the berm through the reinforced portion, or may leadtoward the waste and exit the berm into the waste. The drainage pipesmay ultimately lead to a collection tank for later management or maydischarge into the landfill's leachate collection and treatment system.Each of the plurality of drainage pipes typically pass through theimpermeable membrane via a corresponding boot that is joined to theimpermeable membrane and to the corresponding drainage pipe withimpermeable seams. A drainage layer 158 may be adjacent the insidesurface of the lower sloped outer surface of the impermeable membrane,terminating on one side within the granular fill material. The drainagelayer, which may comprise a geocomposite or any other suitablegeosynthetic drainage media, helps channel any water toward the granularfill and the perforated pipe. The drainage system is an optional featureof all of the illustrated embodiments of the invention. The drainagesystem may vary significantly depending on the requirements of thespecific implementation of the invention. For example, the drainagesystem may omit the plurality of drainage pipes. In such an embodiment,the perforated pipe may drain into a gravel conduit which may extenddownward into the landfill.

Referring now to FIG. 4, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 162 of FIG. 4 is nearly identical to that of FIG. 3. However, theberm of FIG. 4 is illustrated being used with an existing unlinedlandfill, i.e., a landfill in which the surface 178 of thewaste-receiving recess is not lined with a Subtitle D or equivalentliner. Additionally, a third liner portion 176 is disposed between thelower sloped outer surface and the existing accumulation of waste 20.The third liner portion may conform to Subtitle D of RCRA or conform toan approved equivalent of Subtitle D of RCRA. The landfill of FIG. 4also has a Subtitle D or equivalent liner between the existingaccumulation of waste 20 and the future accumulation of waste 130. Asdiscussed above, if the liner portion comprises a Subtitle D orequivalent liner that has a geomembrane layer, the geomembrane thatencapsulates the backfill material may function additionally as thegeomembrane layer of the liner.

The first, second and/or third liner portions illustrated in the variousfigures are all optional. Embodiments of the present invention do notrequire and will not necessarily have or be used with a Subtitle D orequivalent liner.

Referring now to FIG. 5, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 182 of FIG. 2 comprises a reinforced portion 104 and backfillmaterial 192. The reinforced portion 104 is identical to those of FIGS.1-4. The backfill material 192 is similar to that of FIGS. 1-4 but witha different cross-sectional shape. The backfill material 192 of FIG. 5is fully encapsulated by an impermeable membrane 164. As seen in FIG. 5,the berm 182 sits completely on the outer edge of the landfill and nopart of the berm extends over the existing accumulation of waste 20.

The backfill material 192 of berm 182 comprises opposing top and bottomsurfaces, and a sloped outer surface. The sloped outer surface slopesoutward and downward from the top surface to the bottom surface. Thesloped outer surface is adjacent a future accumulation of waste 130. Inthe embodiment of FIG. 5, a first liner portion 120 is disposed betweenthe bottom surface and at least a portion of the edge surface and asecond liner portion 122 is disposed between the sloped outer surfaceand the future accumulation of waste. The first and second linerportions, which are optional, may conform to Subtitle D of RCRA orconform to an approved equivalent of Subtitle D of RCRA.

The berm of FIG. 5 includes a drainage system which comprises aperforated pipe 194, running along at least a portion of the length ofthe berm. The pipe 194 is surrounded by a granular fill material 196. Anoptional plurality of drainage pipes (not illustrated) may each leadsubstantially perpendicularly from the perforated pipe toward the faceand to an area outside of the berm. A drainage layer 198 is adjacent theinside surface of the bottom surface of the impermeable membrane,terminating on one side within the granular fill material. The drainagelayer, which may comprise a geocomposite or any other suitablegeosynthetic drainage media, helps channel any water toward the granularfill and the perforated pipe. In the embodiment of FIG. 5, the edgesurface of the landfill on which the berm sits may be slightly slopeddownward toward the waste-receiving recess to help facilitate the flowof any water toward the drainage system.

Referring now to FIG. 6, a simplified cross-sectional diagram of a bermfor creating a new landfill or laterally increasing the capacity of anexisting landfill is illustrated in accordance with an alternativeembodiment of the present invention. The berm 182 of FIG. 6 is identicalto that of FIG. 5, except that the berm 182 of FIG. 6 is not adjacent anexisting accumulation of waste. Therefore, the berm of FIG. 6 may beused to create an entirely new landfill space—not expanding the capacityof existing landfill. Alternatively, the berm of FIG. 6 may be used tolaterally increase the capacity of an existing landfill. In such analternative use, the berm is situated laterally apart from the existingaccumulation of waste, thereby enabling a new accumulation of waste tobe placed between the berm and the existing accumulation of waste. Thus,the berm of FIG. 6 does not abut or surround any existing waste. Theberm of FIG. 6 is situated to abut or surround a space at which adesired new landfill is to be located. The berm of FIG. 6 is used tocreate the waste-receiving recess into which a future accumulation ofwaste 130 is to be placed.

In embodiments of the invention illustrated in FIGS. 1-6, the innersurface of the reinforced portion and the adjacent inner surface of thebackfill material are substantially planar. In alternative embodimentsof the invention, illustrated in FIGS. 7-12, the inner surface of thereinforced portion and the adjacent inner surface of the backfillmaterial are substantially non-planar. In such embodiments, the innersurface of the reinforced portion and the adjacent inner surface of thebackfill material each comprise a plurality of interlocking sections,such as the zigzag configuration illustrated in FIGS. 7-12. Thenon-planar interlocking sections help facilitate construction of theberm.

Referring now to FIG. 7, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 702 of FIG. 7 is similar to the berm 102 of FIG. 2. However, in theberm 702 of FIG. 7, the inner surface of the reinforced portion and theadjacent inner surface of the backfill material each comprise aplurality of interlocking sections in a zigzag configuration. Berm 702comprises a reinforced portion 704 and backfill material 712. Thereinforced portion 704 is constructed using typical constructiontechniques and comprises structural fill material 706 and a plurality ofreinforcing members 708 disposed therein. The reinforced portion mayhave a foundation of granular fill material 710. The backfill material712 comprises contaminated fill material that is partially encapsulatedby an impermeable membrane 714. In the embodiment of FIG. 7, the portion716 of the backfill material adjacent the existing waste accumulation isnot covered by an impermeable membrane. As in the berm of FIG. 2, theberm 702 has a lower sloped outer surface adjacent the existingaccumulation of waste 20 (the lower sloped outer surface sits on atleast a portion of the existing accumulation of waste), and a uppersloped outer surface adjacent a future accumulation of waste 130 (atleast a portion of the future accumulation of waste sits on the uppersloped outer surface). Also, a liner portion 120 is disposed between thebottom surface and at least a portion of the edge surface and a secondliner portion 122 is disposed between the upper sloped outer surface andthe future accumulation of waste 130. Liner 118 covers the surface ofthe waste-receiving recess.

Referring now to FIG. 8, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 750 of FIG. 8 is similar to the berm 142 of FIG. 3. However, in theberm 750 of FIG. 8, the inner surface of the reinforced portion and theadjacent inner surface of the backfill material each comprise aplurality of interlocking sections in a zigzag configuration. Other thanthe zigzag configuration of the inner surface of the reinforced portionand the adjacent inner surface of the backfill material, all othercomponents of berm 750 of FIG. 8 are the same as the correspondingcomponents of berm 142 of FIG. 3.

Referring now to FIG. 9, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 760 of FIG. 9 is similar to the berm 162 of FIG. 4. However, in theberm 760 of FIG. 9, the inner surface of the reinforced portion and theadjacent inner surface of the backfill material each comprise aplurality of interlocking sections in a zigzag configuration. Other thanthe zigzag configuration of the inner surface of the reinforced portionand the adjacent inner surface of the backfill material, all othercomponents of berm 760 of FIG. 9 are the same as the correspondingcomponents of berm 162 of FIG. 4.

Referring now to FIG. 10, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 770 of FIG. 10 is similar to the berm 182 of FIG. 5. However, inthe berm 770 of FIG. 10, the inner surface of the reinforced portion andthe adjacent inner surface of the backfill material each comprise aplurality of interlocking sections in a zigzag configuration. Other thanthe zigzag configuration of the inner surface of the reinforced portionand the adjacent inner surface of the backfill material, all othercomponents of berm 770 of FIG. 10 are the same as the correspondingcomponents of berm 182 of FIG. 5.

Referring now to FIG. 11, a simplified cross-sectional diagram of a bermfor creating a new landfill or laterally increasing the capacity of anexisting landfill is illustrated in accordance with an alternativeembodiment of the present invention. The berm 780 of FIG. 11 is similarto the berm 182 of FIG. 6. However, in the berm 780 of FIG. 11, theinner surface of the reinforced portion and the adjacent inner surfaceof the backfill material each comprise a plurality of interlockingsections in a zigzag configuration. Other than the zigzag configurationof the inner surface of the reinforced portion and the adjacent innersurface of the backfill material, all other components of berm 780 ofFIG. 11 are the same as the corresponding components of berm 182 of FIG.6.

Referring now to FIG. 12, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill or creating a newlandfill is illustrated in accordance with an alternative embodiment ofthe present invention. Berm 802 of FIG. 12 is similar to berm 182 ofFIG. 6, in that the berm of FIG. 12 is illustrated creating an entirelynew landfill space—not expanding the capacity of existing landfill. Theberm of FIG. 12 does not abut or surround any existing waste. The bermof FIG. 12 is situated to abut or surround a space at which a desirednew landfill is to be located. The berm of FIG. 12 is used to create thewaste-receiving recess into which a future accumulation of waste 830 isto be placed. Berm 802 of FIG. 12 will be particularly useful forexpansion or creation of a landfill in which the waste 830 is FFCPs. Insuch a FFCP landfill, the backfill material 812 may comprise the samewaste material as is disposed of in the landfill. Berm 802 comprises areinforced portion 804 and backfill material 812. The reinforced portion804 is constructed using typical construction techniques and comprisesstructural fill material 806 and a plurality of reinforcing members 808disposed therein. The reinforced portion may have a foundation ofgranular fill material 810. The backfill material 812 comprisescontaminated fill material that is partially encapsulated by animpermeable membrane 814. In the embodiment of FIG. 12, the portion ofthe backfill material adjacent the waste accumulation 830 is not coveredby an impermeable membrane. As in the berm of FIG. 6, the berm 802 has asloped outer surface adjacent a future accumulation of waste 830. Also,a liner portion 820 is disposed between the bottom surface and at leasta portion of the edge surface and the liner portion 820 also covers thesurface of the waste-receiving recess. A liner portion 822 may bedisposed between the future accumulation of waste 830 and the reinforcedportion 804. Liner portion 820 and liner portion 822 may be a subtitle Dliner or equivalent thereof. A drainage system is situated partiallywithin the berm of FIG. 12 and partially within the landfill recess. Thedrainage system comprises a perforated pipe 894, running along a lowpoint of the landfill recess. The pipe 894 is surrounded by a granularfill material 896. In this embodiment, the portion of the drainagesystem within the landfill recess may comprise the landfill leachatecollection system A drainage layer 898 is partially within the backfillmaterial (adjacent the inside surface of the bottom surface of theimpermeable membrane) and partially within the landfill recess,terminating on one side within the granular fill material. The drainagelayer, which may comprise a geocomposite, helps channel any water towardthe granular fill and the perforated pipe.

FIGS. 13-15 illustrate berms of alternative embodiments of theinvention. The berms of FIGS. 13-15 function similarly to the berms ofFIGS. 1-12 in that the berms of FIGS. 13-15 can be used to increase thecapacity of an existing landfill. However, the berms of FIG. 13-15 havea different cross-sectional shape than the berms of FIGS. 1-12.Additionally, the berms of FIG. 13-15 do not have a reinforced portion,although the berms of FIGS. 13-15 have structural fill that couldoptionally be reinforced in a manner similar to that of the reinforcedportions of the berms of FIGS. 2-12 or in any suitable manner. The bermsof FIGS. 13-15 have an overall cross-sectional shape that issubstantially an equilateral trapezoid. Additionally, the backfillmaterial of the berms of FIGS. 13-15 has a cross-sectional shape that issubstantially an equilateral trapezoid. The backfill material of theberms of FIGS. 13-15 is fully encapsulated by an impermeable membrane.

Referring now to FIG. 13, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 300 of FIG. 13 comprises backfill material 312 fully encapsulatedby an impermeable membrane 314 (such as a geomembrane as describedabove). The sloped front face (the surface opposite the waste) and thetop surface of the backfill material are covered by a protectivecovering 306 of structural fill material. A plurality of reinforcingmembers 308 may optionally be disposed therein. The berm sits on theedge surface of the landfill, thereby creating space for a futureaccumulation of waste 130 above the existing accumulation of waste 20.The berms of FIGS. 13-15 may have an optional drainage system similar tothat of the berms of FIGS. 3-6 (the drainage system is an optionalfeature of all of the berms). The drainage system of the berm of FIG. 13comprises a perforated pipe 354 running along at least a portion of thelength of the berm. The pipe 354 is surrounded by a granular fillmaterial 356. An optional plurality of drainage pipes (not illustrated)may each lead substantially perpendicularly from the perforated pipetoward the face and to an area outside of the berm. Each of theplurality of drainage pipes typically pass through the impermeablemembrane via a corresponding boot that is joined to the impermeablemembrane and to the corresponding drainage pipe with impermeable seams.A drainage layer 358 may be adjacent the inside surface of the lowersloped outer surface of the impermeable membrane, terminating on oneside within the granular fill material. The drainage layer, which maycomprise a geocomposite or any other suitable geosynthetic drainagemedia, helps channel any water toward the granular fill and theperforated pipe.

In the embodiment of FIG. 13, a first liner portion 320 is disposedbetween the bottom surface and at least a portion of the edge surfaceand a second liner portion 322 is disposed between the berm and thefuture accumulation of waste 130. The first and second liner portionswill typically conform to Subtitle D of RCRA or conform to an approvedequivalent of Subtitle D of RCRA. As discussed above, if the firstand/or second liner portions comprise a Subtitle D or equivalent linerthat has a geomembrane layer, the geomembrane that encapsulates thebackfill material may function additionally as the geomembrane layer ofthe Subtitle D or equivalent liner. Also as discussed above, theSubtitle D or equivalent liner may be omitted and a geomembrane byitself used in place of the Subtitle D or equivalent liner if permittedby the appropriate governmental authorities. The embodiments of FIGS.13-15 may be used with a landfill with no liner system in place (seeFIG. 13) or with a landfill that has a Subtitle D or equivalent liner118 covering the surface of the waste-receiving recess (see FIG. 14).

A berm according to embodiments of the present invention may be used tocreate a new landfill by constructing one or more such berms around thedesired perimeter of the new landfill. In such an alternativeembodiment, the one or more berms define and create the waste-receivingrecess of the landfill. This is illustrated in FIGS. 14 and 15. FIG. 14illustrates a berm situated adjacent a hole in the ground such that theberm increases the effective size of the waste-receiving recess. Theberm of FIG. 14 may be useful if conditions at the landfill locationprevent the hole from being dug deep enough to create a desired sizedrecess. FIG. 15 illustrates a berm situated adjacent a substantiallyhorizontal ground surface such that the berm creates/defines the entirewaste-receiving recess. The berm of FIG. 15 may be useful if conditionsat the landfill location prevent any hole from being dug to create thedesired recess.

Referring now to FIG. 14, a simplified cross-sectional diagram of a bermfor creating a landfill or laterally increasing the capacity of anexisting landfill is illustrated in accordance with an alternativeembodiment of the present invention. The berm of FIG. 14 is identical tothat of FIG. 13 except that the berm of FIG. 14 is being used to createa new landfill or laterally expand an existing landfill. Thus, the bermof FIG. 14 is not situated adjacent an existing accumulation of wastebut rather is situated adjacent an empty recess or laterally apart froman existing accumulation of waste.

Referring now to FIG. 15, a simplified cross-sectional diagram of a bermis illustrated in accordance with an alternative embodiment of thepresent invention. The berm 400 of FIG. 15 may be used, for example, asa roadway embankment. The berm 400 of FIG. 15 is similar to that ofFIGS. 13 and 14, but the backfill material 312 of the berm 400 of FIG.15 is covered by a protective covering 406 of structural fill materialon the top surface and both sloped surfaces. As in the berms of FIGS. 13and 14, the structural fill material of the berm of FIG. 15 may have aplurality of reinforcing members 308 optionally disposed therein.

In addition to use for increasing the capacity of an existing landfillor creating a new landfill, the berms of embodiments of the inventionmay be used for any purpose typically accomplished by prior art berms.For example, the berms of embodiments of the invention may be used forroadway barriers or levees. The berm 400 of FIG. 15 may be particularlysuited for non-landfill purposes, such as for creating a levee.

Some or all of the protective covering of any of the berms of FIGS.13-15 may be topped with concrete or any other suitable material toincrease the structural strength of the berm and/or to help maintain thestructural fill material in place.

Referring now to FIG. 16, a partial top cutaway view of an optionaldrainage system of a berm is illustrated in accordance with embodimentsof the present invention. FIG. 16 illustrates one possible embodiment ofthe drainage system of the berm of FIG. 5, however the drainage systemsof the other illustrated berms of embodiments of the invention may besimilar to that illustrated in FIG. 16. Many different drainage systemconfigurations may be used in various embodiments of the invention. FIG.16 illustrates the perforated pipe 194 running along the length of theberm within the impermeable membrane 164. The perforated pipe issurrounded by a granular fill material 196. A plurality of drainagepipes 500 (two are illustrated) each lead substantially perpendicularlyfrom the perforated pipe toward the face through the backfill material192 and the structural fill 106 and to an area outside of the berm. Eachof the plurality of drainage pipes typically exits the impermeablemembrane through a corresponding boot 502 that is joined to theimpermeable membrane and to the corresponding drainage pipe withimpermeable seams. The terminal end of each drainage pipe will typicallyhave a valve 504 to control the flow of any infiltrated water out of thedrainage system. Additionally or alternatively, fluid monitoring devicesmay be placed at the terminal end of each drainage pipe.

FIG. 17 illustrates simplified partial cross-sectional diagrams of aSubtitle D landfill liner and two equivalents thereof. FIG. 17Aillustrates the layers of a Subtitle D liner. Layer 600 is the subgrade.Layer 602 is two feet of clay with a specified permeability. Layer 604is a geomembrane (typically a 60 mil HDPE geomembrane). Layer 606 iseighteen inches of coarse granular material (e.g., aggregate or sand).FIG. 17B illustrates the layers of a liner that is typically consideredto be equivalent to a Subtitle D liner. Layer 600 is the subgrade. Layer608 is a geosynthetic clay liner (GCL). Layer 610 is a geomembrane(typically a 60 mil HDPE geomembrane). Layer 612 is either ageocomposite or eighteen inches of coarse granular material (e.g.,aggregate or sand). FIG. 17C illustrates the layers of a liner that istypically considered to be equivalent to a Subtitle D liner. Layer 600is the subgrade. Layer 608 is a geomembrane laminated geosynthetic clayliner. Layer 616 is either a geocomposite or eighteen inches of coarsegranular material (e.g., aggregate or sand).

FIGS. 18, 19 and 20 each illustrate a simplified cross-sectional diagramof a berm in accordance with alternative embodiments of the presentinvention. The berms of FIGS. 18, 19 and 20 are similar, respectively,to the berms of FIGS. 13, 14 and 15. However, the berms of FIGS. 18, 19and 20 have a backfill material that has a pyramidal (rather thanfrusto-pyramidal) cross-sectional shape. Referring now to FIG. 18, asimplified cross-sectional diagram of a berm for increasing the capacityof an existing landfill is illustrated in accordance with an alternativeembodiment of the present invention. The berm 700 of FIG. 18 comprisespyramidal (rather than frusto-pyramidal) backfill material 712 fullyencapsulated by an impermeable membrane 314 (such as a geomembrane asdescribed above). The sloped front face (the surface opposite the waste)of the backfill material is covered by a protective covering 306 ofstructural fill material. In all other respects, the berm of FIG. 18 isthe same as the berm of FIG. 13.

Referring now to FIG. 19, a simplified cross-sectional diagram of a bermfor creating a landfill or laterally increasing the capacity of anexisting landfill is illustrated in accordance with an alternativeembodiment of the present invention. The berm of FIG. 19 is identical tothat of FIG. 18 except that the berm of FIG. 19 is being used to createa new landfill or laterally expand an existing landfill. Thus, the bermof FIG. 19 is not situated adjacent an existing accumulation of wastebut rather is situated adjacent an empty recess or laterally apart froman existing accumulation of waste. The berm 700 of FIG. 19 comprisespyramidal (rather than frusto-pyramidal) backfill material 712 fullyencapsulated by an impermeable membrane 314 (such as a geomembrane asdescribed above). The sloped front face (the surface opposite the waste)of the backfill material is covered by a protective covering 306 ofstructural fill material. In all other respects, the berm of FIG. 19 isthe same as the berm of FIG. 14.

Referring now to FIG. 20, a simplified cross-sectional diagram of a bermfor creating a landfill or laterally increasing the capacity of anexisting landfill is illustrated in accordance with an alternativeembodiment of the present invention. The berm 800 of FIG. 20 comprisespyramidal (rather than frusto-pyramidal) backfill material 812 fullyencapsulated by an impermeable membrane 414 (such as a geomembrane asdescribed above). The sloped front face (the surface opposite the waste)and the sloped back face (the surface adjacent the future accumulationof waste) of the backfill material is covered by a protective covering406 of structural fill material. In all other respects, the berm of FIG.20 is the same as the berm of FIG. 15. As with the berm of FIG. 15, theberm 800 of FIG. 20 may be particularly suited for non-landfillpurposes, such as for creating a levee.

Some or all of the protective covering of any of the berms of FIGS.18-20 may be topped with concrete or any other suitable material toincrease the structural strength of the berm and/or to help maintain thestructural fill material in place.

The apices of the pyramidal cross-section of the backfill material ofFIGS. 18, 19 and 20 are illustrated as being generally pointed. However,in alternative embodiments of the inventions, the apices of thepyramidal cross-section of the backfill material of FIGS. 18, 19 and 20may be generally rounded.

Referring now to FIG. 21, a simplified cross-sectional diagram of a bermfor increasing the capacity of an existing landfill is illustrated inaccordance with an alternative embodiment of the present invention. Theberm 852 of FIG. 21 is similar to that of FIG. 4. However, in the bermof FIG. 21, impermeable membrane 860 encapsulates more than just thebackfill material 152. Specifically, impermeable membrane 860 alsoencapsulates at least a portion of the fill material 856 that is used tocreate the reinforced portion 854. As illustrated in FIG. 21 and asdescribed in more detail above, the reinforced portion 854 comprises aplurality of reinforcing members 858 disposed (typically horizontally)therein. As illustrated in FIG. 21 and in more detail in FIG. 23, thereinforcing members 858 extend from and are typically attached to orintegral with the wall-facing material. As such, the impermeablemembrane 860 cannot simply be placed substantially vertically adjacentthe face of the reinforced portion, as the reinforcing members obstructan uninterrupted placement of the membrane. Therefore, the portion ofthe membrane adjacent the face of the reinforced portion comprisesmultiple segments that each span from one reinforcing member to anadjacent reinforcing member, as described in more detail below relativeto FIG. 23. The impermeable membrane thereby at least partiallyencapsulates at least a portion of one or more reinforcing members.

The berm of FIG. 21 may further comprise a column 862 of granularmaterial or geosynthetic drain (e.g., Geocomposite, etc.) to help drainany moisture that may be present in the fill material 856. Such agranular column may be especially helpful if the fill material comprisesa fine-grained material that does not shed moisture well. Such agranular column may not be needed if the fill material comprises asufficiently coarse-grained material. The granular column in FIG. 21 isillustrated as planar and substantially vertical, although alternativeembodiments of the invention may utilize non-planar columns and/orcolumns that are other than substantially vertical.

Referring now to FIG. 22, a simplified cross-sectional diagram of a bermfor creating a landfill or increasing the capacity of an existinglandfill is illustrated in accordance with an alternative embodiment ofthe present invention. The berm 902 of FIG. 22 is similar to that ofFIG. 5. However, in the berm of FIG. 22 (as in the berm of FIG. 21),impermeable membrane 910 encapsulates more than just the backfillmaterial 192. Specifically, impermeable membrane 910 also encapsulatesat least a portion of the fill material 906 that is used to create thereinforced portion 904. As in FIG. 21, the reinforced portion 904 ofFIG. 22 comprises a plurality of reinforcing members 908 disposed(typically horizontally) therein, and the portion of the membraneadjacent the face of the reinforced portion comprises multiple segmentsthat each span from one reinforcing member to an adjacent reinforcingmember, as described in more detail below relative to FIG. 23. Theimpermeable membrane thereby at least partially encapsulates at least aportion of one or more reinforcing members. As in FIG. 21, the berm ofFIG. 22 may further comprise a column 912 of granular material to helpdrain any moisture that may be present in the fill material 906. Such agranular column may not be needed if the fill material comprises asufficiently coarse-grained material. The granular column in FIG. 22 isillustrated as planar and substantially vertical, although alternativeembodiments of the invention may utilize non-planar columns and/orcolumns that are other than substantially vertical.

Referring now to FIG. 23, a simplified cross-sectional diagram of aportion of the berm of FIG. 21 is illustrated. The correspondingcomponents of the berm of FIG. 22 may also be configured as illustratedin FIG. 23. The berm portion of FIG. 23 comprises two wall-facingcomponents 870 a, 870 b (e.g., wire baskets), corresponding reinforcingmembers 858 a, 858 b, and impermeable membrane 860 (comprising threeportions—860 a, 860 b and 860 c). The reinforcing members typicallycomprise one or more transverse bars 864 a, 864 b along their lengths.The transverse bars may be larger and more substantial than theremainder of the reinforcing members.

The top portion 860 a of the impermeable membrane extends from thebackfill material (not illustrated, but off the right side of FIG. 23,and illustrated in FIGS. 21 and 22) into the reinforced portion and isimpermeably affixed to one of the reinforcing members. The top portion860 a of the impermeable membrane will typically extend into thereinforced portion at or about the level of one of the reinforcingmembers and be impermeably affixed to that nearest member. The portionof the impermeable membrane off the right side of FIG. 23 forms the topportion of the impermeable membrane 860 shown in FIG. 21. In FIG. 23,the top portion 860 a of the impermeable membrane is impermeably affixedto member 858 a. The top portion 860 a of the impermeable membrane isimpermeably affixed to member 858 a using any suitable technique,including but not limited to gluing, extrusion welding, solvent welding,or fusion welding, thereby creating an impermeable joint 872.

To continue the impermeable membrane vertically (or substantiallyvertically) along the inner surface of the face of the reinforcingportion, a relatively narrow section 860 b of impermeable membrane isaffixed on one side (the top side) to the underside of reinforcingmember 858 a and on the other side (the bottom side) to the top side ofreinforcing member 858 b to span the gap between the two reinforcingmembers and to create an impermeable barrier across that gap. The narrowsection 860 b of the impermeable membrane is impermeably affixed tomember 858 a and 858 b using any suitable technique, including but notlimited to gluing, extrusion welding, solvent welding, or fusionwelding, thereby creating two impermeable joints 872.

Another relatively narrow section 860 c may be affixed to the undersideof reinforcing member 858 b and to another reinforcing member (notillustrated) below reinforcing member 858 b. This spanning of gapsbetween two adjacent reinforcing members may continue along the entireheight of the wall, or along as much of the height of the wall asdesired, to create the vertical or near vertical portion of theimpermeable encapsulation. At the bottom of the vertical or nearvertical portion of the impermeable encapsulation (not illustrated), abottom portion of the impermeable membrane will extend back toward thebackfill material as illustrated in FIGS. 21 and 22.

Although it is not illustrated in FIG. 23 because FIG. 23 is across-section, it will be appreciated that the illustrated sections ofthe impermeable membrane extend a substantial distance along the lengthof the berm (and possibly along the entire length) to effectivelyencapsulate much or all of the backfill material and a significantportion of the fill material.

The vertical (or substantially vertical) portion of the impermeablemembrane may be positioned any desired distance from the inner surfaceof the face of the reinforced portion, although a distance of 2-4 feetmay be desirable.

FIGS. 21 and 22 illustrate specific embodiments in which the impermeablemembrane encapsulates a portion of the fill material and (potentially) aportion of one or more of the reinforcing members. It should beappreciated that any specific embodiment of the invention (including butnot limited to any embodiments specifically described and/or illustratedherein) may comprise an impermeable membrane that encapsulates a portionof the fill material and (potentially) a portion of one or more of thereinforcing members. For example, specific concepts of embodiments ofthe invention illustrated in FIGS. 21 and 22 would work equally well inthe berms of FIGS. 2-15 and 18-20, and such berms are within the scopeof the invention and this application. Further, embodiments of theinvention in which the impermeable membrane encapsulates a portion ofthe fill material and (potentially) a portion of one or more of thereinforcing members include embodiments in which the impermeablemembrane encapsulates (a) some portion of one reinforcing member, (b)some portion of two or more reinforcing members, (c) all of onereinforcing member, or (d) all of two or more reinforcing members.

In all embodiments of the invention, the fill material used to createthe reinforced portion (e.g., fill material 106 used to createreinforced portion 104 of FIG. 4) may comprise clean structural fill ormay comprise contaminated soil/media, provided the contaminatedsoil/media can be amended or manipulated to meet the parameters providedby a design engineer and can meet regulatory approval.

Construction of a berm according to embodiments of the inventiongenerally begins with site improvements, infrastructure relocation, andsubgrade preparation. Depending on site conditions, improvements ofleachate and/or gas collection systems may be required prior toconstruction of the berm. Decommissioning and/or relocation ofmonitoring wells, gas probes, water/sewer lines, communications and/orelectricity cables, stormwater features, and other appurtenances may benecessary. This work will generally be performed prior to subgradepreparation. The existing subgrade along the berm footprint may requirecut/fill in order to bring existing grades to the proposed base gradeelevations, as specified in the construction drawings. Depending on thefoundation conditions, foundation improvements (e.g., deep soil mixing,soil columns) may be required prior to construction of the berm.

To construct the berm, clean structural fill or contaminated soil/media(provided the contaminated soil/media can be amended or manipulated tomeet the parameters provided by a design engineer and can meetregulatory approval) shall be used in the reinforced portion of theberm. Suitable contaminated backfill material (as described above) is tobe used in the non-reinforced portion of the berm. To facilitate uniformcompaction of both the structural fill and the backfill material, theconstruction of the berm shall typically be carried out in the followingsteps:

1. Place and compact 1.5 foot thick (although thickness may vary basedon the design parameters of the specific berm) lifts of structural fillas specified in the construction drawings with baskets on the face ofthe berm (or other acceptable wall facing material as specified).

2. Each basket shall have a welded wire form along the face of the bermto allow for top soil placement and facing construction.

3. A layer of 1.5 feet (although thickness may vary based on the designparameters of the specific berm) of structural fill shall be placed overa layer of geogrid (the geogrid is used as the reinforcing members).

4. A wrap geotextile is typically wrapped around the face to preventtopsoil from eroding before vegetation is established.

5. The structural fill shall extend from the wall facing to at least thespecified length of the geogrid, from where it ties in to the existingsurface on a 0-10:1 (horizontal:vertical) slope.

6. Typically, four 1.5 foot thick lifts shall be installed followingsteps 1-5. Depending on the configuration of the wall at a specificsite, fewer lifts may be constructed at a given time but, typically, nomore than four lifts will be constructed in one sequence.

7. Install the impermeable membrane (e.g., geomembrane) along the 0-10:1(horizontal:vertical) slope to allow for separation between structuralfill and CCB/contaminated media.

8. Place backfill material in 12 inch lifts to match the total thicknessof the structural fill (typically 6 feet).

9. Weld the geomembrane, flip the geomembrane over the backfill materiallayer, and extend to the next structural fill/backfill material tie-inpoint.

10. Construct the next lifts of structural fill as outlined in steps1-6.

11. Repeat the backfill material construction procedure outlined inSteps 7-9.

12. Repeat steps 10 and 11 until the berm is complete.

The construction of the berm of FIGS. 21-23 shall typically be carriedout in the following steps:

-   -   1. Place and compact 1.5 foot thick (although thickness may vary        based on the design parameters of the specified berm) lifts of        structural fill as specified in the construction drawings with        baskets on the face of the berm (or other acceptable wall facing        material as specified).    -   2. Each lift shall have a welded wire form (basket) along the        face of the berm to allow for top soil placement and facing        construction.    -   3. Facing materials used in conjunction with the baskets shall        be rolled out along the forms.    -   4. A layer of structural geogrid (reinforcing members) shall be        placed up to the welded wire form. The layer of structural        geogrid may be connected to the facing depending on the type of        facing material used.    -   5. At a suitable distance from the wall face (typically 3-4        feet) a 2-foot wide sheet of impermeable geomembrane is welded        longitudinally down the structural geogrid transverse bars to        form a continuous joined seam on the top surface of the        structural geogrid. Once welded in place the geomembrane will        form a vertical hydraulic barrier that is substantially parallel        with the face of the berm. Sections of structural geogrid can be        joined on the landfill side of the geomembrane by appropriately        designed and specified splicing method bars.    -   6. A 1.5-foot thick compacted layer of structural fill shall be        placed over a layer of geogrid (the geogrid is used as the        reinforcing members).    -   7. At a suitable distance from the wall face (typically 3-4        feet) a 2 feet width sheet of impermeable geomembrane is welded        longitudinally down the structural geogrid transverse bars to        form a continuous joined seam on the bottom surface of the        structural geogrid. Sections of structural geogrid can be joined        by appropriately designed and specified bodkin bars.    -   8. Topsoil shall be placed at the face of the berm and the wrap        geotextile and/or erosion mat and biaxial geogrid are typically        wrapped around the topsoil to prevent the face from eroding        before vegetation is established.    -   9. The structural fill shall extend from the wall facing to at        least the specified length of the geogrid, from where it ties in        to the backslope which is a geomembrane lined slope.    -   10. Construct the next lift of structural fill as outlined in        steps 1-9.11. Repeat step 10 until berm is complete.

Referring now to FIGS. 24-29, simplified cross-sectional diagrams ofsystems for strengthening a sloped structure, including but not limitedto a sloped structure such as a berm, basin, levee, embankment, or thelike (hereinafter referred to collectively as “containment structures”)are illustrated in accordance with alternative embodiments of thepresent invention. FIGS. 24-29 each illustrate alternative systems forstrengthening a sloped wall of a containment structure 920 that mightcontain, support, or hold back some material 922. For example, thecontainment structure might be a levee that contains water or a bermthat contains trash (as in a landfill). Alternatively, the containmentstructure might be an embankment, such as a road embankment such thatthe road surface is supported on top of the embankment. Such containmentstructures may be constructed of a variety of different materials. Abasic berm may be created simply by mounding soil. More complex bermsmay have a rock or gravel substrate, topped by clay and/or soil. It maybe desirable to strengthen/buttress the sloped wall(s) of such acontainment structure, especially if the failure/breaching of thecontainment structure may cause significant property damage, personalinjury, or loss of life. It is desirable to have a system and method tostrengthen/buttress the sloped wall(s) of such a containment structurewithout having to rebuild or significantly modify the containmentstructure itself. The slope strengthening system of embodiments of theinvention may be constructed adjacent the existing sloped wall of acontainment structure, or may be constructed after the sloped wall ofthe containment structure is “cut back” (i.e., some material is removedfrom the sloped wall; typically more material is removed from the bottomthan from the top, thereby steepening the slope).

FIGS. 24-29 are cross-sectional views. It should be appreciated that thecontainment structures are generally elongated structures that typicallyspan a significant distance (e.g., typically as little as hundreds offeet to as much as many miles). The strengthening system may adjoin itscorresponding containment structure for much or all of that distance, ormay adjoin its corresponding containment structure for only a smallportion in situations in which only a small portion needs to bestrengthened.

The systems for strengthening a sloped wall of a structure such as aberm, basin, levee, embankment, or the like of embodiments of thepresent invention generally comprise encapsulated fill material, withhorizontal strengthening members disposed within the fill material, thatis constructed in place against the sloped wall of the containmentstructure. FIGS. 24-27 illustrate embodiments in which the opposingsides of the strengthening system are generally parallel to each other,have generally the same slope as the sloped wall, and are generallyabout the same height as (or are somewhat shorter than) the containmentstructure. FIG. 28 illustrates an embodiment in which the opposing sidesof the strengthening system are generally parallel to each other, havegenerally the same slope as the sloped wall, but are generally tallerthan the containment structure and has a portion that partially or fullycovers the top of the containment structure. FIG. 29 illustrates anembodiment in which the opposing sides of the strengthening system havedifferent slopes (such that the opposing sides meet at a peak) and aregenerally about the same height as (or are somewhat shorter than) thecontainment structure. The side of the strengthening system that adjoinsthe sloped wall of the containment structure will, of course, havegenerally the same slope as the sloped wall because of this adjoiningrelationship.

The strengthening system 930A of FIG. 24A comprises first 934 and second946 opposing sides, with the second side being adjacent the sloped wall,a top side 931 adjoining top edges of the first and second sides, and abottom side 941 adjoining bottom edges of the first and second sides,thereby forming a cavity within the first, second, top, and bottomsides. As mentioned above, the first and second sides are substantiallyparallel to each other in the embodiment of FIG. 24A. The strengtheningsystem 930A further comprises fill material 936 disposed within thecavity. An impermeable membrane 932 encapsulates at least a portion ofthe fill material. The strengthening system 930A further comprises aplurality of reinforcing members 938 (typically horizontally) disposedwithin the fill material. The first side 934 has opposing inner andouter surfaces. The outer surface is commonly termed the “face” and theinner surface is adjacent the fill material. The system may optionallyhave facing material covering the face of the reinforced portion. Thefacing material, if present, is typically attached to or integral withthe reinforcing members. The bottom side and at least a portion of thefirst and second sides may be positioned below grade 921 as illustrated.This below-grade placement of a portion of the strengthening systemhelps prevent any sliding motion of the bottom side away from the slopedstructure which could weaken and perhaps cause the destruction of thestrengthening system. This below-grade placement is an optional featureof all embodiments of the invention.

The reinforcing members are typically disposed within the cavity in asubstantially horizontal arrangement, and extend from the first sidetoward the second side. The reinforcing members are typically comprisedof geogrid. The strengthening system of embodiments of the inventionwill typically comprise at least one or two layers of geogrid, but thenumber of layers will generally depend on the steepness, width, anddepth of the strengthening system.

The fill material may comprise structural fill material or contaminatedfill material. The fill material may comprise structural fill, thattypically comprises relatively homogeneous soils that are relativelyfree of debris, foreign objects, excess silt, roots, and organics. Thecontaminated fill material can be any suitable waste product that hasthe desired coarseness, shear strength, high friction angle, and highbearing capacity. The contaminated fill material should benon-hazardous, but is nonetheless expensive to properly dispose of. Thecontaminated fill material may comprise FFCPs, non-hazardouscontaminated soils, contaminated crushed glass, contaminated crushedconcrete, contaminated crushed asphalt, sand blast grit, foundry sands,properly de-watered dredge spoils, and combinations of these materials.Importantly, the fill material is fully encapsulated or at leastpartially encapsulated by an impermeable membrane 932.

The impermeable membrane is, when intact, impermeable to fluids and/orgases. The impermeable membrane used in embodiments of the invention maycomprise, for example, a geomembrane, a compacted low permeability clayliner, a geosynthetic clay liner (GCL), geomembrane laminatedGeosynthetic Clay Liner, etc., or liner systems that will typicallyconform to Subtitle D of the Resource Conservation and Recovery Act(RCRA), conform to an approved equivalent of Subtitle D of RCRA(described in further detail below), or conform to a liner and/or coversystem requirement of any appropriate regulatory agency. The geomembranemay comprise one of low-density polyethylene (LDPE), high-densitypolyethylene (HDPE), polyvinyl chloride (PVC), polyurea or polypropylene(PP). Because of the potentially large size of such a berm and thelimited size of commercially available geomembranes, the impermeablemembrane may comprise a plurality of impermeable membrane sectionsjoined with impermeable seams. The plurality of impermeable membranesections are typically joined using any desirable method of joining suchmaterial, including but not limited to extrusion welding, solventwelding, fusion welding, and/or gluing (especially for PVC or PP).

Similarly as described above in relation to FIGS. 21-23, the reinforcingmembers extend from and are typically attached to or integral with thewall-facing material, and as such, the impermeable membrane cannotsimply be placed substantially vertically adjacent the first side, asthe reinforcing members obstruct an uninterrupted placement of themembrane. Therefore, the portion of the membrane adjacent the first sidemay comprise multiple segments that each span from one reinforcingmember to an adjacent reinforcing member, as described in detail above.The impermeable membrane thereby at least partially encapsulates atleast a portion of one or more reinforcing members.

The strengthening system 930A of FIG. 24A may comprise a drainage systemwithin the impermeable membrane, the drainage system comprising aperforated pipe 944 surrounded by a granular fill material 942.Similarly as described above in relation to other figures, an optionalplurality of drainage pipes (not illustrated) may each leadsubstantially perpendicularly from the perforated pipe to an areaoutside of the cavity. The drainage pipes may either lead toward thefirst side and exit the cavity through the first side, or may leadtoward the content 922 and exit the cavity into the content. Thedrainage pipes may ultimately lead to a collection tank for latermanagement or may (where the strengthening system is used to strengthena landfill wall) discharge into the landfill's leachate collection andtreatment system. Each of the plurality of drainage pipes typically passthrough the impermeable membrane via a corresponding boot that is joinedto the impermeable membrane and to the corresponding drainage pipe withimpermeable seams. The strengthening system 930A of FIG. 24 may have afoundation of granular fill material 940.

FIG. 24B illustrates a strengthening system 930B which is nearlyidentical to strengthening system 930A of FIG. 25A, but strengtheningsystem 930B of FIG. 24B comprises a somewhat different drainage system.As illustrated in FIG. 24B, the drainage system comprises a perforatedpipe 944 surrounded by a granular fill material 942. However, thegranular fill material 942 of strengthening system 930B extends from thefirst side to the second side rather than just being positioned in acorner of the cavity (this is an optional feature of all embodiments ofthe invention). FIG. 24B shows the perforated pipe 944 being closer tothe first side, but the perforated pipe could be positioned at anysuitable location within the granular fill material. Additionally,multiple perforated pipes could be used. As mentioned above, an optionalplurality of drainage pipes (not illustrated) may each leadsubstantially perpendicularly from the perforated pipe to an areaoutside of the cavity. FIG. 24B also illustrates that a perforated pipe945 may be placed within the foundation of granular fill material 940(this is an optional feature of all embodiments of the invention).

FIG. 24C illustrates a strengthening system 930C which is nearlyidentical to strengthening system 930B of FIG. 24B, but in thestrengthening system 930C of FIG. 24C, the bottom side comprises adownwardly extending keyed portion 943 that fits within a correspondingdepression in the surface beneath the bottom side (this keyed portion isan optional feature of all embodiments of the invention). This keyedportion helps prevent any sliding motion of the bottom side away fromthe sloped structure which could weaken and perhaps cause thedestruction of the strengthening system (thereby providing furtherprevention of sliding motion in addition to the below-grade placement ofthe bottom portion of the strengthening system). The keyed portion maybe more useful on relatively wider strengthening systems (i.e.,strengthening systems in which the distance between the first and secondsides is relatively greater). As in the strengthening system 930B ofFIG. 24B, the strengthening system 930C of FIG. 24C may comprise aperforated pipe 945 placed within the foundation of granular fillmaterial 940. In such an optional embodiment, the perforated pipe 945may be placed in the portion of the foundation that corresponds to thekeyed portion, as this is the lowest portion and would thereby betterfacilitate drainage.

FIGS. 25-27 illustrate alternative embodiments of a strengthening systemof embodiments of the invention. The embodiments of FIGS. 25-27 aresimilar to that of FIGS. 24A-C. However, the embodiments of FIGS. 25-27further comprise a drainage layer to facilitate the flow of any liquidwithin the cavity toward the drainage system. Such a drainage layer maybe placed (i) adjacent an inner surface of the impermeable membrane andadjacent a portion of the impermeable membrane that is adjacent thesecond side; (ii) adjacent an inner surface of the impermeable membraneand adjacent a portion of the impermeable membrane that is adjacent thebottom side; (iii) adjacent the sloped wall and adjacent an outersurface of the impermeable membrane; and/or (iv) adjacent the bottomside and adjacent an outer surface of the impermeable membrane. Morespecifically, FIG. 25 illustrates alternative strengthening system 960in which the drainage layer 948 is outside of the impermeable membraneand along both the second side and the bottom side. FIG. 26 illustratesalternative strengthening system 970 in which the drainage layer 950 isinside the impermeable membrane and along both the second side and thebottom side. FIG. 27 illustrates alternative strengthening system 974 inwhich the drainage layer 948 is outside of the impermeable membrane andalong both the second side and the bottom side and in which the drainagelayer 950 is inside the impermeable membrane and along both the secondside and the bottom side. While FIGS. 25-27 all illustrate a drainagelayer along both the second and bottom sides, the drainage layers may belocated along only the second side or along only the bottom side of anyof these embodiments. The drainage layer may comprise a geosyntheticdrainage media or a granular material. The granular material istypically well graded sand, well graded sand and gravel, crushed stone,or other approved granular material.

FIG. 28 illustrates a further alternative embodiment of a strengtheningsystem 980 of embodiments of the invention. The embodiment of FIG. 28 issimilar to that of FIG. 24. However, in the embodiment of FIG. 28, thefill material extends over the top edge of the second side 946, over thetop edge of the sloped wall, and over the top of the containmentstructure 920. This extension of the fill material may help furtherstrengthen the containment structure. This extension of the fillmaterial may be encapsulated by the impermeable membrane as illustrated.A drainage layer may be located between the top of the containmentstructure and the extension of the fill material. This drainage layermay be adjacent an outer surface of the impermeable membrane (asillustrated by element 948 of FIG. 28), adjacent an inner surface of theimpermeable membrane, or both.

FIG. 29 illustrates a further alternative embodiment of a strengtheningsystem 984 of embodiments of the invention. The embodiment of FIG. 29 issimilar to that of FIG. 24. However, in the embodiment of FIG. 29, theslope of the first side 950 is greater than a slope of the second side946 such that top edges of the first and second sides adjoin. As such,the cross-sectional shape of the strengthening system 984 of FIG. 29 isan obtuse triangle. While FIG. 29 illustrates a drainage layer 948adjacent an outer surface of the impermeable membrane, the embodiment ofFIG. 29 may instead or additionally comprise a drainage layer adjacentan inner surface of the impermeable membrane.

To construct the slope strengthening system, contaminated soil/media (itmay be desirable for the contaminated soil/media to be amended ormanipulated to meet the parameters provided by a design engineer and canmeet regulatory approval) shall typically be used as the fill material.To facilitate uniform compaction of the fill material, the constructionof the slope strengthening system of FIGS. 24-29 shall typically becarried out in the following steps (if typical mechanically stabilizedearthen wall construction with wire baskets is utilized) (wire basketsare typically not used if the slope of the face is greater than about1.5:1):

1. Place and compact 1.5 foot thick (although thickness may vary basedon the design parameters of the specified berm) lifts of fill materialas specified in the construction drawings with baskets on the face ofthe berm (or other acceptable wall facing material as specified). Thefirst lift may be a granular drainage layer or geosynthetic equivalentas specified by the design engineer.

2. Each lift shall have a welded wire form (basket) along the face ofthe berm to allow for top soil placement and facing construction.

3. Facing materials used in conjunction with the baskets shall be rolledout along the forms.

4. A layer of structural geogrid (as reinforcing members) shall beplaced up to the welded wire form. The geogrid may be connected to thefacing depending on the type of facing material used.

5. At a suitable distance from the wall face (typically 3-4 feet) a2-foot wide sheet (or greater as specified) of impermeable geomembraneis welded longitudinally down the structural geogrid transverse bars toform a continuous joined seam on the top surface of the structuralgeogrid. Once welded in place, the geomembrane will form a verticalhydraulic barrier that is parallel with the face of the slopestrengthening system. Sections of structural geogrid can be joined onthe containment structure side of the geomembrane by appropriatelydesigned, specified, and placed bodkin bars.

6. A 1.5-foot thick compacted layer of fill material shall be placedover a layer of geogrid (the geogrid is used as the reinforcingmembers). Additional compacted layers of fill material shall be placedover previous layers if required and specified.

7. Topsoil shall be placed at the face of the slope strengthening systemand the wrap geotextile and/or erosion mat and biaxial geogrid aretypically wrapped around the topsoil to prevent the face from erodingbefore vegetation is established.

8. At a suitable distance from the wall face (typically 3-4 feet) a twofeet width sheet of impermeable geomembrane (or greater if specified) iswelded longitudinally down the structural geogrid transverse bars toform a continuous joined seam on the bottom surface of the structuralgeogrid. Sections of structural geogrid can be joined by appropriatelydesigned and specified bodkin bars.

9. The fill material placed in Step 6 shall extend from the impermeablegeomembrane to at least the specified length of the geogrid, from whereit extends to the backslope which is a geomembrane lined slope.

10. Construct the next lift of fill material as outlined in steps 1-9.

11. Repeat the construction procedure outlined in Steps 10.

12. Repeat steps 10 and 11 until the berm is complete.

The construction of the slope strengthening system of FIGS. 24-29 shalltypically be carried out in the following steps (if no typical wirebasket wall facing utilized):

1. Place and compact 1.5 feet thick (although thickness may vary basedon the design parameters of the specified berm) lifts of fill materialas specified in the construction drawings. The first lift may be agranular drainage layer or geosynthetic equivalent as specified by thedesign engineer.

2. A layer of structural geogrid (reinforcing members) shall be placedup to the exterior edge with a transverse bar as the outside edge. Itmay be connected to the facing depending on the type of facing materialif used.

3. The required width sheet of impermeable geomembrane is weldedlongitudinally down the structural geogrid transverse bars to form acontinuous joined seam on the top surface of the structural geogrid.Once welded in place the geomembrane will form a vertical hydraulicbarrier that is parallel with the face of the slope strengtheningsystem. Sections of structural geogrid can be joined on the landfillside of the geomembrane by appropriately designed and specified bodkinbars if needed.

4. A 1.5-foot thick compacted layer of fill material shall be placedover a layer of geogrid (the geogrid is used as the reinforcingmembers). Additional compacted layers of structural fill shall be placedover previous layers as required and specified.

5. The previously installed and welded impermeable geomembrane is weldedlongitudinally down the structural geogrid transverse bars to form acontinuous joined seam on the bottom surface of the structural geogrid.Sections of structural geogrid can be joined by appropriately designedand specified bodkin bars if required.

6. Topsoil shall be placed at the face of the berm and the wrapgeotextile and/or erosion mat and biaxial geogrid are typically wrappedaround the topsoil to prevent the face from eroding before vegetation isestablished.

7. The fill material shall extend from the wall facing to at least thespecified length of the geogrid, from where it ties in to the backslopewhich is a geomembrane lined slope.

8. Construct the next lift of fill material as outlined in steps 1-7.

9. Repeat the backfill material construction procedure outlined in Steps8.

10. Repeat steps 8 and 9 until the slope strengthening system iscomplete.

Many modifications and other embodiments of the invention will come tomind to one skilled in the art to which this invention pertains havingthe benefit of the teachings presented in the foregoing descriptions andthe associated drawings. Therefore, it is to be understood that theinvention is not to be limited to the specific embodiments disclosed andthat modifications and other embodiments are intended to be includedwithin the scope of the appended claims. Although specific terms areemployed herein, they are used in a generic and descriptive sense onlyand not for purposes of limitation.

1. A system for strengthening a sloped structure, the system comprising:first and second opposing sides, the second side being adjacent thesloped structure; a bottom side adjoining bottom edges of the first andsecond sides, thereby forming a cavity within the first, second, andbottom sides; fill material disposed within the cavity; an impermeablemembrane encapsulating at least a portion of the fill material; and aplurality of reinforcing members disposed within the fill material. 2.The system of claim 1, wherein the first and second sides aresubstantially parallel to each other.
 3. The system of claim 2, furthercomprising a top side adjoining top edges of the first and second sides,such that the cavity is formed within the first, second, top, and bottomsides.
 4. The system of claim 2, wherein the fill material extends overa top edge of the second side and over a top of the sloped structure. 5.The system of claim 1, wherein a slope of the first side is greater thana slope of the second side such that top edges of the first and secondsides adjoin.
 6. The system of claim 1, wherein the plurality ofreinforcing members are disposed within the cavity in a substantiallyhorizontal arrangement.
 7. The system of claim 6, wherein the pluralityof reinforcing members extend from the first side toward the secondside.
 8. The system of claim 1, wherein the fill material comprisescontaminated fill material.
 9. The system of claim 1, wherein theimpermeable membrane comprises a geomembrane.
 10. The system of claim 9,wherein the geomembrane comprises one of low-density polyethylene(LDPE), high-density polyethylene (HDPE), polyvinyl chloride (PVC),polyurea or polypropylene (PP).
 11. The system of claim 1, wherein theimpermeable membrane comprises a plurality of impermeable membranesections joined with impermeable seams.
 12. The system of claim 11,wherein the plurality of impermeable membrane sections are joined usinggluing, extrusion welding, solvent welding, or fusion welding.
 13. Thesystem of claim 11, wherein one or more impermeable membrane sectionsare joined to reinforcing members adjacent opposing sides of theimpermeable membrane sections.
 14. The system of claim 11, wherein atleast one impermeable membrane section is joined to one adjacentreinforcing member above the at least one impermeable membrane sectionand one adjacent reinforcing member below the at least one impermeablemembrane section.
 15. The system of claim 1, wherein the fill materialis fully encapsulated.
 16. The system of claim 1, further comprising: adrainage system within the impermeable membrane, the drainage systemcomprising a perforated pipe surrounded by a granular fill material. 17.The system of claim 16, wherein the drainage system further comprises aplurality of drainage pipes each leading from the perforated pipe to anarea outside of the cavity; wherein each of the plurality of drainagepipes exits the impermeable membrane through a corresponding boot thatis joined to the impermeable membrane and to the corresponding drainagepipe with impermeable seams.
 18. The system of claim 14, furthercomprising: a drainage layer that is (i) adjacent an inner surface ofthe impermeable membrane adjacent a portion of the impermeable membranethat is adjacent the second side; (ii) adjacent an inner surface of theimpermeable membrane adjacent a portion of the impermeable membrane thatis adjacent the bottom side; (iii) adjacent the sloped structure andadjacent an outer surface of the impermeable membrane; and/or (iv)adjacent the bottom side and adjacent an outer surface of theimpermeable membrane.
 19. The system of claim 18, wherein the drainagelayer comprises a geosynthetic drainage media or a granular material.20. The system of claim 1, wherein the bottom side and at least aportion of the first and second sides are below grade.
 21. The system ofclaim 1, wherein the bottom side comprises a downwardly extending keyedportion that fits within a corresponding depression in a surface beneaththe bottom side.
 22. A method for strengthening a sloped structure, themethod comprising: constructing a strengthening system adjacent thesloped structure, the strengthening system comprising: first and secondopposing sides, the second side being adjacent the sloped structure; abottom side adjoining bottom edges of the first and second sides,thereby forming a cavity within the first, second, and bottom sides;fill material disposed within the cavity; an impermeable membraneencapsulating at least a portion of the fill material; and a pluralityof reinforcing members disposed within the fill material.
 23. The methodof claim 22, wherein the first and second sides are substantiallyparallel to each other.
 24. The method of claim 23, wherein thestrengthening system further comprises a top side adjoining top edges ofthe first and second sides, such that the cavity is formed within thefirst, second, top, and bottom sides.
 25. The method of claim 23,wherein the fill material extends over a top edge of the second side andover a top of the sloped structure.
 26. The method of claim 22, whereina slope of the first side is greater than a slope of the second sidesuch that top edges of the first and second sides adjoin.
 27. The methodof claim 22, wherein the plurality of reinforcing members are disposedwithin the cavity in a substantially horizontal arrangement.
 28. Themethod of claim 27, wherein the plurality of reinforcing members extendfrom the first side toward the second side.
 29. The method of claim 22,wherein the fill material comprises contaminated fill material.
 30. Themethod of claim 22, wherein the impermeable membrane comprises ageomembrane.
 31. The method of claim 30, wherein the geomembranecomprises one of low-density polyethylene (LDPE), high-densitypolyethylene (HDPE), polyvinyl chloride (PVC), polyurea or polypropylene(PP).
 32. The method of claim 22, wherein the impermeable membranecomprises a plurality of impermeable membrane sections joined withimpermeable seams.
 33. The method of claim 32, wherein the plurality ofimpermeable membrane sections are joined using gluing, extrusionwelding, solvent welding, or fusion welding.
 34. The method of claim 32,wherein one or more impermeable membrane sections are joined toreinforcing members adjacent opposing sides of the impermeable membranesections.
 35. The method of claim 32, wherein at least one impermeablemembrane section is joined to one adjacent reinforcing member above theat least one impermeable membrane section and one adjacent reinforcingmember below the at least one impermeable membrane section.
 36. Themethod of claim 22, wherein the fill material is fully encapsulated. 37.The method of claim 22, wherein the strengthening system furthercomprises a drainage system within the impermeable membrane, thedrainage system comprising a perforated pipe surrounded by a granularfill material.
 38. The method of claim 37, wherein the drainage systemfurther comprises a plurality of drainage pipes each leading from theperforated pipe to an area outside of the cavity; wherein each of theplurality of drainage pipes exits the impermeable membrane through acorresponding boot that is joined to the impermeable membrane and to thecorresponding drainage pipe with impermeable seams.
 39. The method ofclaim 35, wherein the strengthening system further comprises a drainagelayer that is (i) adjacent an inner surface of the impermeable membraneadjacent a portion of the impermeable membrane that is adjacent thesecond side; (ii) adjacent an inner surface of the impermeable membraneadjacent a portion of the impermeable membrane that is adjacent thebottom side; (iii) adjacent the sloped structure and adjacent an outersurface of the impermeable membrane; and/or (iv) adjacent the bottomside and adjacent an outer surface of the impermeable membrane.
 40. Themethod of claim 39, wherein the drainage layer comprises a geosyntheticdrainage media or a granular material.
 41. The method of claim 22,wherein the bottom side and at least a portion of the first and secondsides are positioned below grade.
 42. The method of claim 22, whereinthe bottom side comprises a downwardly extending keyed portion that fitswithin a corresponding depression in a surface beneath the bottom side.